In the absence of a depalletizing and dispensing apparatus for unloading stacked items from a pallet, it has been necessary for a laborer to manually remove stacked items such as packaged products, cases, crates or the like from the pallet. Dispensing of stacked items in this manner is inefficient, laborious, and expensive. In an attempt to remedy this problem, a number of unloading machines designed to depalletize loads or dispense a load of stacked pallets have been developed over the years. In this respect, depalletizers and unloaders which attempt to replace manual labor for preparing pallets, or items stacked thereon, for further processing and eventual reuse, are widely known in various forms.
For example, U.S. Pat. No. 3,139,993 to Lauer discloses a pallet unloader that removes stacked boxes from a pallet, and then sequentially removes each box from the bottom of the stack. The pallet and boxes are removed by an hydraulic ram which pushes the removed items onto a conveyor for further processing. U.S. Pat. No. 3,069,050 to Brettrager shows a pallet dispensing apparatus that removes the bottom pallet, sequentially, from a stack of pallets. The bottom pallet is separated from the pallet stack by a reciprocable carriage having tines that are inserted into the second pallet from the bottom to raise that pallet and those stacked on top of it. The carriage lifts the stack so that the bottom pallet remains alone on the roller bed, which in conjunction with a drive chain, sweeps the pallet away for further processing.
Unfortunately, depalletizers known in the prior art are themselves relatively expensive and difficult to adapt for unloading different types of loads. For example, the beverage industry recently began packaging beverage products in plastic (2 liter or 20 oz.) beverage containers. Consequently, plastic crates or cases were developed for accommodating a predetermined number (e.g. four) of plastic beverage containers at one time, and were designed to be stackable on pallets for loading multiple cases and multiple levels of such cases onto a single pallet. After the product is delivered, the empty cases are generally restacked on the pallets and returned to the plant for reuse. Heretofore, the returned cases had to be manually unloaded from the pallets because none of the existing unloading technology could be used, or adapted for use, with the plastic cases at an economical cost. Hence, there has been an unaddressed need for an affordable machine that is capable of automatically and adaptably depalletizing and dispensing palletized loads, especially with respect to cases of plastic beverage containers and the like.